The Ontario Building Code | Protection of Structural Members
3.2.3.9. Protection of Structural Members
(1) Structural members, including beams, columns and arches, placed wholly or partly outside an exterior face of a building that are less than 3 m from the property line or centreline of a public thoroughfare shall be protected from exterior fire by fire protection having a fire-resistance rating not less than that required by Articles 3.2.2.20. to 3.2.2.83. for their protection from interior fires, but not less than 1 h.
(2) Structural members of heavy timber construction, including beams, columns and arches, placed wholly or partly outside an exterior face of a building and 3 m or more from the property line or centreline of a public thoroughfare need not be covered with noncombustible cladding.
In Plain Language
This clause sets specific limiting-distance and opening rules for exterior walls facing an open public space, like a street, park, or permanent open area, generally allowing a more generous unprotected opening allowance than walls facing directly onto a shared property line.
This is a plain-language summary of the 2012/2017 Ontario Building Code text above, for general understanding only and not a substitute for the Code. Always confirm current requirements against the 2024 edition (O.Reg. 163/24) or a qualified professional before construction.